Effect of Beef Silver Skin (Epimysium) Levels on Meat Emulsion Stability, Quality Attributes, and Texture Parameters.

The epimysium, also known as silver skin, is a fascia of connective tissue that surrounds each muscle. During fabrication, epimysium is removed from intact cuts, and it can be used as a source of collagen in processed meats to reduce production costs. However, little is known about the emulsifying properties of this collagen source. Thus, this study aimed to evaluate the effect of three levels of beef epimysium (silver skin, 0, 5, and 10%) on meat emulsion stability and on its cooked characteristics. Beef silver skin partially replaced ground beef, pork, and fat trimming, while all the other ingredients remained constant across formulations. The inclusion of silver skin did not affect (p > 0.05) chemical composition, total cooking loss, water loss, and raw emulsion color. Cooking fat loss linearly increased (p = 0.02) while cooked emulsion L* linearly decreased (p = 0.04) as silver skin level increased. Hardness, gumminess, and chewiness decreased linearly as silver skin levels increased (p < 0.01). Overall, incorporating silver skin into meat emulsions reduced stability, increased fat loss, and led to a weaker cooked emulsion matrix.

Effects of cutting time and maceration on preference and nitrogen balance in beef steers fed mixed birdsfoot trefoil-timothy grass hay cut at sunrise or sundown.

Forages cut at sundown usually contain a greater concentration of nonstructural carbohydrates (NSC) than those cut at sunrise. Maceration can speed up the rate of moisture loss of cut forage during field drying and reduce NSC utilization by plant cells. We aimed to evaluate the effects of cutting time and forage maceration on feed preference, apparent total tract digestibility of nutrients, and N balance in growing steers. A mixed sward of birdsfoot trefoil and timothy grass was divided into two halves, with the first half cut at sundown (1800 h) after a sunny day and the second half at sunrise (0600 h) the next day. Approximately 50% of the sundown- and sunrise-cut herbage were macerated. Forages were harvested as hay resulting in four treatments: 1) sunrise-cut hay (AM); 2) AM plus maceration (AM-M); 3) sundown-cut hay (PM); and 4) PM plus maceration (PM-M). Hays were offered as the sole feed source to four crossbred steers (296.1 ± 7.25 kg) according to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 21 d with 14 d for diet adaptation and 7 d for collection. Hays cut at sundown had 15% greater NSC than those cut at sunrise. A cutting time by maceration interaction was found (P < 0.05) for intake and apparent digestibility of crude protein (CP), indicating that these two variables decreased more when maceration was applied to sundown- versus sunrise-cut hays. Similarly, interaction effects were observed (P < 0.05) for total digestible nutrients and digestible energy, showing that maceration decreased the energetic value of sundown-cut hays but did not change that of sunrise-cut hays. Steers fed hays cut at sundown had decreased urinary N excretion and improved retained N (P < 0.05), whereas N retention was reduced by maceration (P < 0.05). In addition, six crossbred steers were used to assess feed preference, 2 wk before (period 1) and 1 wk after (period 2) the digestibility trial. Animals were randomly assigned to receive a sequence of the four hays combined in pairs. The intake rate was greater for sundown- than sunrise-cut hays, and it was decreased by maceration. Steers showed the greatest preference for PM hay, while AM-M was the most rejected. In conclusion, shifting forage cutting from sunrise to sundown increased hay NSC concentration, which resulted in improved N utilization and preference. Forage maceration during field drying decreased CP concentration and N retention in beef steers under the conditions of our study.

Explaining meat quality of bulls and steers by differential proteome and phosphoproteome analysis of skeletal muscle.

The objective of this study was to evaluate the differential proteome and phosphoproteome between bulls and steers during conversion of muscle to meat, as well as after 14 days of aging. Twelve male Nellore (Bos taurus indicus) calves were used, and six calves were randomly selected for surgical castration. Calves were fed the same diet and were harvested after 230 days on feed. Longissimus muscle was sampled just after stunning (0d postmortem), at deboning (1d postmortem) and after aging (14d postmortem) for differential proteome analysis. Castration upregulated (P < 0.05) the abundance of glycolytic enzymes, while the oxidative phosphorylation protein ATP5B was downregulated (P < 0.05). In addition, abundance of troponin T fast isoform (TNNT3) was upregulated by castration (P < 0.05), while the slow isoform (TNNT1) tended to be decreased (P < 0.10). The creatine kinase M-type was markedly fragmented postmortem. Abundance of phosphorylated PGM1 increased during the first 24 h postmortem and was highly correlated with carcass pH. Further, abundance of the phosphorylated myofibrillar proteins ACTA1 and MYLPF were positively correlated with sarcomere shortening. Overall, our finds demonstrated that abundance and phosphorylation of glycolytic enzymes are associated with changes in beef tenderness and intramuscular fat. SIGNIFICANCE: The design of the present study allowed to clarify the key proteins related to changes during conversion of muscle to meat such as pH decline and sarcomere shortening. In addition, the correlation between some biomarker and meat quality traits were confirmed.

Effect of post-weaning growth rate on carcass traits and meat quality of Nellore cattle.

This study evaluated the effects of growth rate during post-weaning growing phase on carcass traits and beef quality. Thirty-four Nellore young bulls were randomly assigned to one of three treatments: LOW, MEDIUM or HIGH growth rate during post-weaning growing phase followed by high growth rate in the finishing phase. The growth rate affected (P<0.05) all carcass traits evaluated at the end of post-weaning growing phase, except ultimate pH. Carcass dressing was greatest (P<0.05) for the HIGH growth rate group in both phases. Beef from the HIGH group exhibited the greatest (P<0.05) sarcomere length and a* and b* colour values at the end of post-weaning growing phase. However, post-weaning growth rate did not affected (P>0.05) collagen content and solubility, myofibrillar fragmentation index and Warner-Bratzler shear force. Our data suggest that a low post-weaning growth rate produces lighter and leaner carcasses, but it does not affect meat quality traits in Nellore young bulls.

Design and heterologous expression of dengue virus envelope protein (E) peptides and their use for serological diagnosis.

Viruses belonging to the Flaviviridae family are found and distributed in most of the tropical and sub-tropical regions of the world. The genus has more than 56 members, most of which cause clinical symptoms in humans. The clinical diagnosis of dengue requires laboratory confirmation because of the similarity of symptoms with a series of other acute fevers and the primary use antibodies or antigens for detection. In this work, peptides E(1) and E(2) of the envelope protein (E) of the dengue virus were mapped using bioinformatics methods. These peptides were then expressed in a prokaryotic system and purified. An indirect ELISA for antibodies IgG and IgM from laboratory samples previously characterised was then used with the peptides to detect anti-dengue antibodies. For IgG using the peptide E(1), the sensitivity of the indirect ELISA was 88.3% and the specificity was 56%; using the peptide E(2), the sensitivity was 90% and the specificity was 59%; and using a combination of both peptides, the sensitivity was 93.3% and the specificity was 78%. For IgM using the peptide E(1), the sensitivity was 88% and the specificity was 66%; using the peptide E(2), the sensitivity was 88% and the specificity was 69%; and when used in combination, the peptides E(1)/E(2) demonstrated a sensitivity of 90% and a specificity of 86%. These results indicate that the use of the E(1) and E(2) peptides of the E protein are an alternative for serological diagnosis of dengue fever.

Como avaliar o paciente com doença muscular / How to evaluate the patient with neuromuscular diseases

Muitas säo as patologias que podem afetar o músculo esquelético. Entre essas estäo as doenças de causa inflamatória como poliomiosite ou doença do tecido conectivo, doenças endócrinas, patologias genéticas e desordens metabólicas, doenças do sistema nervoso central e periférico. A história do paciente pode ajudar a estabelecer a severidade dos sintomas. O exame físico deve tentar quantificar a força muscular do paciente e avaliar outros aspectos da funçäo muscular para detectar movimentos anormais e alteraçöes de reflexos. Análise bioquímica do músculo através de exames enzimáticos (enzimas e mioglobulinas), eletromiografia e biópsia muscular também podem auxiliar e, muitas vezes, confirmar o diagóstico

Distraçäo da placa epifisiária: estudo experimental / Distraction of epiphyseal plate: experimental study

Um estudo experimental foi realizado na extremidade distal do f6emur em nove coelhos com doze semnas de vida, com o propósito de identificar o mecanismobásico envolvido na distraçao da fise, quando empregada uma taxa de distraçao de 1,0mm, numa única vez ao dia e de avaliar a viabilidade do segmento alongado. Os animais foram divididos em três grupos de acordo com a época em que foram mortos (final do alongamento, 30 e 60 dias após o alongamento). Os resultados radiográficos mostraram em todos os espécimes uma diastase da epífise de metáfise (GAP) entre o segundo e o quinto dia após o início do alongamento. Sessenta dias após o período distracional, ficou evidenciado radiograficamente que todo o segmento alongado estava ossificado. A distraçao de 1,0mm, numa única vez ao dia (epifisiólise distracional) da placa espifisária, provou ser eficaz na obtençao de alongamento ósseo em coelhos, pois levou à formaçao de um osso novo com características morfológicas e funcionalmente semelhantes ao osso normal. Portanto, esse método de alongamento é mais uma opçao para correçao de discrepância entre os membros.